C#教程之接口用法(转)

using System;

/// <summary>

/// 创建一个获取字符串数据的接口

/// </summary>

///

interface IGetData
{
    //接口定义，不使用修饰符

    string GetText();
    void SetText(string str);
    string Content { get;set;}
}
//创建一个获取整数的接口

interface IGetInt
{
    int GetInt();
    void SetInt(int num);
    int Integer { get;set;}
}
//接口的继承

interface IGetDataExt : IGetData
{
    string CopySelf();
}
//实现一个接口

public class Data : IGetData
{
    //实现GetText成员函数

    public string GetText()
    {
        return content;
    }
    //实现SetText成员函数

    public void SetText(string str)
    {
         content = str;
    }
    //实现Content属性，指定为public

    public string Content
    {
         get
        {
            return content;
        }
         set
        {
             content = value;
        }
    }
    private string content;
};

//实现两个接口

public class StringInt : IGetData, IGetInt
{
    //实现GetText成员函数

    public string GetText()
    {
        return content;
    }
    //实现SetText成员函数

    public void SetText(string str)
    {
         content = str;
    }
    //实现Content属性，指定为public

    public string Content
    {
         get
        {
            return content;
        }
         set
        {
             content = value;
        }
    }

    //实现GetInt

    public int GetInt()
    {
        return integer;
    }
    //实现SetInt

    public void SetInt(int num)
    {
         integer = num;
    }
    //实现Integer属性

    public int Integer
    {
         set
        {
             integer = value;
        }
         get
        {
            return integer;
        }
    }
    private int integer;
    private string content; 
}

//实现继承的接口　

public class DataExt : IGetDataExt
{
    //实现GetText成员函数

    public string GetText()
    {
        return content;
    }
    //实现SetText成员函数

    public void SetText(string str)
    {
         content = str;
    }
    //实现Content属性，指定为public

    public string Content
    {
         get
        {
            return content;
        }
         set
        {
             content = value;
        }
    }
    public string CopySelf()
    {
        return content + content;
    }
    private string content; 
}

//override接口的方法

public class VirtualData : IGetData
{
    //定义为一个虚方法

    public virtual void SetText(string str)
    {
        Console.WriteLine("VirtualData.SetText");
         content = str;

    }
    //非虚方法

    public string GetText()
    {
        Console.WriteLine("Virtual.GetText");
        return content;
    }
    public string Content
    {
         get
        {
            return content;
        }
         set
        {
             content = value;
        }
    }
    private string content;
}
//override类实现

public class OverrideData : VirtualData
{
    //override类的virtual方法

    public override void SetText(string str)
    {
        Console.WriteLine("Override.SetText");
         content = str;
    }
    //非virtual的方法

    public new string GetText()
    {
        Console.WriteLine("Override.GetText");
        return content;
    }
    private string content;
}

public class CallData
{
    //Data的测试类

    public static void test()
    {
        //测试一个接口的字符串接口

        Data data = new Data();
        data.SetText("SetText");
        Console.WriteLine(data.GetText());
        data.Content = "Content";
        Console.WriteLine(data.Content);

        //测试两个接口的接口　

         StringInt si = new StringInt();
         si.SetText("StringInt.SetText");
         si.SetInt(100);
        Console.WriteLine("{0},{1}", si.GetText(), si.GetInt());

         si.Content = "StrigInt.Content";
         si.Integer = 200;
        Console.WriteLine("{0},{1}", si.GetText(), si.GetInt());

        //测试继承接口

         DataExt de = new DataExt();
         de.SetText("DataExt.SetText");
         de.CopySelf();
        Console.WriteLine(de.Content);

        //接口的强制转化

         StringInt SICast = new StringInt();
         SICast.SetText("SICast.SetText");
         SICast.SetInt(300);
         IGetData DataCast = (IGetData)SICast;
        Console.WriteLine(DataCast.Content);

         IGetInt IntCast = (IGetInt)SICast;
        Console.WriteLine(IntCast.Integer);

        //is关键字的使用

        if (SICast is IGetData)
            Console.WriteLine("Implemented from IGetData,{0}",SICast.GetText());
        else
            Console.WriteLine("SICast is not implemented from IGetData");
        
        //as关键字的使用

         IGetData DataAS = SICast as IGetData;
        if (DataAS != null)
            Console.WriteLine("Implemented from IGetData,{0}", SICast.GetText());
        else
            Console.WriteLine("SICast is not implemented from IGetData");

        //override与new在类中的使用

         IGetData vd = new OverrideData();
        //调用Override.SetText

         vd.SetText("VirtualData.SetText");
        //调用Virtual.Get

         vd.GetText();
        
         OverrideData od = new OverrideData();
        //调用Override.SetText

         od.SetText("OverrideData.SetText");
        //调用Override.GetText

         od.GetText();
    }
};